화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.101, No.47, 9757-9766, 1997
Electroaggregation of Silver Interfacial Colloids
Electric field-induced aggregation of interfacial colloids was studied in the absence and in the presence of ion deposition with special attention to the morphology and growth rates of the deposit and their implications for the nature of the underlying growth processes. The processes were studied as a function of several experimental parameters, namely, the magnitude of the voltage, the protocol of its application (DC, AC), the concentration and species of the metallic ions, the conductivity of the aqueous subphase, and the nature of the organic subphase. Pure electroaggregation was found to produce slowly developing and highly ramified structures. Pure electrodeposition of silver ions, when the colloid is absent, is similarly slow and produces compact disklike deposits, with rough edges (under most of the experimental conditions employed here). When both processes are active, a faster growth rate is observed, with a morphology between those of the two limiting processes. We suggest a cooperative mechanism for the growth process, bridge-aggregation, that combines aggregation and ion deposition, mutually accelerating each other, and that accounts well for the observed phenomena.